Control device for power lift mechanisms



'H. M. JOHNSTON ET AL. CGNTROL DEVICE FQR POWER LIFT MECHANISMS FiledApril 15, 1 938 Fig.1

ATTORNEY.

Patented Dec. 5, 1939 Parent OFFlCE CONTROL DEVICE FOR POWER LIFTMECHANISMS Howard Milton Johnston and- Peder Bjerre,

Toronto, Ontario, Canada, assign'ors to- Massey- Harris Company,Limited, Toronto,"

Canada Ontario,

Application April 15, 1938, Serial No. 202,268

7 Claims. (Cl. 97-244) This invention relates to cultivating or seedingimplements and the like and more specifically to a depth and clearancecontrolling device for the shovels, discs or the like of suchimplements.

The object of the invention is to provide a device which, in associationwith the power lift of a cultivator or other implement, is adjustable tocontrol the extent of lift and drop of the shovels, discs or the like ofthe implement whereby adequate ground clearance of the shovels may beobtained always, regardless of the extent towhich the shovels may enterthe ground in operation.

Another object is to provide a device of the character described which,in addition to performing the functions referred to, acts to holdagainst up and down movement the cultivating or drilling units at anylevel at which they may be positioned.

In a broad aspect, the invention comprises the provision,- inassociation with the rock' shaft through which the earth-engaging unitsof a cultivator or the like are raised or lowered, of 'means forrotating the rock shaft through a wide range of movement in eitherdirection to raise or lower the units and means for varying the extentof such rotative movement. The invention will be described withreference to the accompanying drawing, in which, Figure 1 is a partialside View of a cultivator including the invention, and

Figure 2 is an enlarged sectional view showing details of the invention.

In the drawing, l indicates one of the two carrying wheels of thecultivator, 2 being the axle supported thereby. 3 is a square rock shaftand 4 is one of several rocker arms secured thereto. Each rocker arm hasa connection at its end with a spring-pressed link 5, which is connectedto a cultivator beam 6 carrying a cultivator tooth i, which may beprovided with the usual spring trip device, not shown. Pressure exertedon the beam 6 by the spring 5 is regulated by rotation of the rock shaftby usual manual means not shown. The construction thus far described isof a conventional nature and need not be referred to in detail.

Mounted on and fitting over the square rock shaft is a cylindricalbearing 8 having an integral flange 9 at one'end and a detachable collarI at 0 the other end, the collar being fixed by means of a pin i i whichpasses through the collar, bearing and shaft. Mounted for free rotationon the bearing 8 adjacent the collar I0 is a cam member l2 havingagroove or channel l3 in one face ported on the to form opposing innerand outer cam surfaces It and I5. I i

Means for revolving the cam member about the bearing 8 and shaft 3 andfor holding it in any fixed position comprises a gear segment I6, formedintegral with the cam member, and a worm ll meshingtherewith. The wormI1 is carried by a shaft l8 mounted in a frame [9 sup,- bearing 8adjacent the flange 9, a bearing ring 20 being provided between themeet- 1() ing faces of cam member l2 andframe IS. The frame 50 is fixedin position bymeans of a connection 2! to a member 22 of the maincultivator frame. The worm I] is actuated by rotation of the shaft It,as by means of a crank, not shown, positioned for easy access by theoperator.

A bracket 23 is fixed to the rock shaft adjacent the cam member H! bymeans of a complementary clamping member 24 and bolts 25. A bell-pulllever 26 is pivotally mounted in a lower extension of the bracket 23 bymeans of a stud 2i, and a roller 28 carried by a pin 29 in the bellpullextends into the groove l3 of the cam member, the outer periphery of theroller having engagement with both inner and outer cam surfaces I l andI5.

The lower extremity of the, bell-pull is connected by means of a pitman30 with the conventional power lift, not shown, of the cultivator.

In operation, the'cam member i2 is placed in a 30 predeterminedpositiornby actuation of the worm H, to obtain the desired extent ofupward or downward movement of the cultivator teeth and the power liftplaced in operation. The power lift, acting through pitman 30, bell-pull26, and bracket 23, will rotate the rock shaft in either direction toobtain a-lifting or lowering action of the teeth as desired, thebell-pull being fulcrumed by means of roller 28 on cam surface I5,during a lifting action, or on cam surface I4, 40 during aloweringaction.

The extent of rotation of the rock shaft in either direction and theconsequent extent of upward or downward movement of the cultivator teethobviously will be determined by the posi- 5 tion of the fulcrum point onthe cam surfaces l4 and 5 with respect to the rock shaft. Thus, with theparts in the position shown in Figure 1, with the initial fulcrum pointof the bell-pull in the Zone of greatest distance from the rock shaft,the

latter will be rotated, by a given movement of the power lift pitmanthrough a longer are than that possible by the same movement of thepitman if the initial fulcrum point were in a zone of less distance fromthe rock shaft. As previousthe usual means for exerting pressure on theshovels or the like to force them more. deeply into the earth. l-

The double-acting surfaces of the cam member also act to hold firmly therock shaft, in any fixed position. Thus, should soft ground orhol'es beencountered by the earth-engaging units, such units will not drop butwill be maintained at the determined level.

We claim:

I 1. In an implement having a wheel-supported frame, a rock'shaft and aplurality of earth-en gaging units mounted in said frame, said rockshaft having a connection with said units and being'rotatable to raiseand lower said units, means for imparting rotative movement to said rockshaft comprising a pitman and a lever pivotally connected to said pitmanand to said rock shaft,-an adjustable member adapted to provide afulcrumpoint for said lever, and means for adjusting said member to varythe position of said fulcrum point whereby the extent of said'rotativemovement in response to a given pitman stroke is varied.

2. In an implement having a wheel-supported frame, a rock shaft and aplurality of earth-engaging units mounted in said frame, said rock shafthaving a connection with said units and being rotatable toraise andlower said units, means for imparting rotative movement to said rockshaft comprising a pitman and a lever pivotally connected to said pitmanand to said rock shaft, an adjustable member having a cam surf-ace'adapted to provide a fulcrum point for said lever, and means foradjusting said member to vary the position of the fulcrum point on saidcam surface whereby the extent of said rotative movementin response to agiven pitman stroke is varied.

3. In an implement having a wheel-supported frame, a rock shaft and aplurality of earth-engaging, units mounted in said frame, said rockshaft having a connection with said unitsand being rotatable to raiseand lower said units, means for imparting rotative movement to said rockshaft comprising a pitman and a lever pivotally connected to said pitmanand to said rock shaft, --a cam member rotatably mounted on said rockshaft and providing a fulcrum point for said lever,

2,181,994 7 v W w and means for rotating said cam member and 1 lever.

:said opposed cam surfaces.

holding it in any fixed position. v

4. In an implement having a'wheel-supported frame, a rock shaft and aplurality of earth-engaging units mounted in said frame, said rock shafthaving a connection with said units and being rotatable to raise andlower said units, means for imparting rotative movement 'to said rockshaft comprising a pitman and a leverpivotally connected to said pitmanand to said rock shaft,

a cam member mounted for adjustive rotative "movement on said rock shaftand having opposed cam surfaces thereon, one of said cam surfaces beingadapted toprovide a fulcrum point for said 5. In an implement having 'awheel-supported frame, a rock shaft and a plurality of earth-engagingunits mounted in said frame, said rock shaft having a connection withsaid units and being rotatable to raise and lower said units, means forimparting "rotative movement .to said rock shaft comprising a pitman, -abell-pull lever pivotally connectedxto said pitman and to said real:shaftja cam member rotatably mounted on said rock shaft and providing afulcrum point for said lever, 'andumeans for rotating said cam memberand holding it in any fixed position comprising a gear segment carriedby the cam member and a worm meshing with said gear segment.

' 6. In an implement having a wheel-supported frame, a rock shaft and aplurality of earth-en- .gaging, ,units mounted in said frame, said rockshaft having a connection with said units and being rotatable to raiseand lower said units, means for imparting rotative movement to said rockshaft comprising a pitman a bell-pull lever pivotally connected to saidpitman'and to said rock shaft, an extension on said lever on which it isadapted to fulcrum, and a. cam member mounted foradjustablerotativemovement on said rock frame, a rock shaft and aplurality of earth-engaging units mounted in saidframe, said rock ingrotatable toraise and lower said units, means for imparting rotativemovement to said rock shaft comprising a pitman, 'a bell-pull leverpivotally connected to said pitman and to said rock shaft, a rollercarried by said lever and on which said lever is adapted tofulcrum,.anda cam member mounted for adjustable rotative movement onsaid rock shaft, said cam member. having a channeltherein.providingopposed camsurfaces, said roller extending into saidchannel and engaging HOWARD MILTO JOHNSTON. PEDER BJERRE.

4o shaft, said lever extension engaging on said cam 'member '7; In: animplement having a wheel-supported 5,45 shaft having a connection withsaid units and be-

